With ever decreasing size of electronic devices utilized in ULSI (ultra-large-scale integrated) circuits, there has emerged the problem of increased capacitance of intralayers and/or interlayers, causing signal delays. Therefore, there has been a need to develop a low dielectric constant (k) material having a k-value lower than that of the conventional silicon dioxide (SiO2) or fluorinated silicon oxide (SiOF).
U.S. Pat. No. 6,147,009 discloses a low dielectric constant material produced by reacting the vapor of a precursor containing atoms of Si, C, O and H in a parallel plate plasma enhanced chemical vapor deposition chamber, the precursor being a molecule with a ring structure such as 1,3,5,7-tetramethylcyclotetrasiloxane(TMCTS, C4H16O4Si4), tetraethylcyclotetrasiloxane(C8H24O4Si4) or decamethylcyclopentasiloxane(C10H30O5Si5), with or without added oxygen. However, the dielectric constant of the disclosed film is still high, in the range of 3.3 to 4.0. To further reduce the dielectric constant of the material described in the patent, U.S. Pat. No. 6,312,793 proposes a low k material consisting of two or more phases. However, the multi-phase material still has a k-value of more than 3.2.
Accordingly, the present inventors have endeavored to develop a novel material having a dielectric constant lower than those of conventional materials.